Almost all passenger motor vehicles presently produced include some type of impact deployed restraint system to protect vehicle occupants, or others, during a vehicle impact event. Such restraint systems may include, for example, front and side airbags within the passenger compartment, side curtains, inflatable seat belts, and seat belt pretensioners. Sensing systems and methods typically control the deployment of such restraints by determining the severity of a vehicle impact event.
During most impact events, the opportunity to provide occupant restraint exists only for a very brief period of time. Furthermore, inadvertent deployment of a restraint, such as an airbag, is undesirable. Therefore, to be most effective, impact deployed restraints must deploy quickly when needed, and only when actually needed. To this end, impact systems implement methods to allow the systems to discriminate between severe and relatively harmless impact events and to also be insensitive to mechanical inputs which are not associated with crash events. More importantly, however, the sensor are configured to allow for rapid detection of the impact event and transmission of relevant information for effective deployment. The need for a sensor having a method or process which allows for rapid deployment decisions is particularly great with side airbags, where the crush zone is much smaller than that associated with front airbags, and the time available for a deployment decision is likewise shorter.